Pollution Flashcards
What are the primary methods used to minimize military aircraft noise?
- Avoiding major urban areas
- Varying flight paths
- Requesting temporary stops to low-level flight paths
- Compensating for damage to livestock or property
- Avoiding ecologically sensitive areas
How does the timing and number of flights affect civil aircraft noise nuisance?
The level of noise nuisance around an airport is affected by the timing and number of flights each day
What design considerations are made for new airports to reduce noise impact?
- Built away from major population centers
- Aircraft taxiing areas away from residential areas
- Engine test areas located away from residential areas
- Acoustic insulation in buildings
- Land use restrictions
What is a high bypass-ratio engine?
Modern jet engines with a second tube and a turbofan that reduces noise by smoothing exhaust flow
What are chevron nozzles used for in aircraft engines?
They mix bypass air with surrounding air more smoothly, making engines quieter
What are engine hush kits?
Devices that work similarly to chevron nozzles to reduce engine noise
What is the purpose of engine acoustic liners?
To absorb noise inside the outer cowling and around the inner cowling
How do blended wing aircraft help reduce noise?
Engines located on top of the aircraft act as a barrier to reduce noise reaching the ground
What aerodynamic features help reduce noise in aircraft design?
- Fairings on the undercarriage
- Covering wing flap hinges
- Welded panels instead of riveted construction
What is the effect of a steep take-off angle on aircraft noise?
Allows the aircraft to climb rapidly to an altitude where it cannot be heard
What are noise limits for aircraft?
Aircraft are categorized into groups depending on the noise they make
What is the quota count system used at Heathrow, Gatwick, and Stansted?
Aircraft types are allocated points based on noise levels, and airlines must not exceed a certain number of points
True or False: Supersonic civil airliners are currently in operation.
False
Which type of train is generally the noisiest?
High speed passenger trains
What general methods are used to control industrial noise?
- Sound absorbing surfaces and materials
- Acoustic mats
- Remote machinery operation
- Ear protection for workers
What types of domestic noise are commonly encountered?
- Washing machines
- Music equipment
- Garden machinery
- DIY power tools
- Barking dogs
What are some control measures for domestic noise?
- Acoustic absorbers on appliances
- Wearing ear defenders with power tools
- Volume limiters on music equipment
- Control of pet dogs
